International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 10 | October 2025
p-ISSN: 2395-0072
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Study of Thermodynamic Parameters with Ionic Conductivity in Lithium Salt-Solvent Mixtures Dr. Vandana Chauhan1 1Department of Physics, Kishori Raman (P.G) College, Mathura 281001.
Dr Bhimrao Ambedkar University Agra 282004. ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - The study of thermodynamic parameters with
(EC), propylene carbonate (PC) and dimethyl carbonate (DMC). These solvent systems offer high dielectric constants and low viscosity, which facilitate efficient ion transport. However, temperature fluctuations significantly influence ion mobility and solvent-ion interactions, thus affecting the conductivity and stability of electrolytes [3].
ionic conductivity in lithium salt-solvent mixtures provide crucial insights into ion transport mechanisms and electrolyte stability for advanced lithium batteries. Work is the interaction between temperature, ionic mobility and solution thermodynamics, different lithium salts (such as LiPF₄, LiBF₄ and LiClO₄) were dissolved in organic solvents (ethylene carbonate, dimethyl carbonate and propylene carbonate). The Arrhenius and Vant H off equations were used to determine parameters like Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) from temperature-dependent conductivity measurements. The findings show that increased Ionic dissociation and solvent dielectric characteristics cause ionic conductivity to rise exponentially with temperature. While positive ΔS indicates more molecular instability, negative ΔG findings validate spontaneous ion transport. In lithium-based energy storage systems, this study helps the optimization of salt-solvent combinations for enhanced conductivity, stability and electrochemical performance. Results in the case of ionic conductivity increased with temperature, ΔG was negative, ΔH positive and ΔS indicated enhanced ion dissociation and molecular disorder.
The conductivity (σ) of such systems often follows an Arrhenius-type behaviour, expressed as: σ = σ0 e −Ea /RT where E_a is the activation energy, R is the gas constant and T is the absolute temperature. From these measurements, thermodynamic quantities like ΔG, ΔH, and ΔS can be derived, providing a complete thermodynamic picture of ionic conduction [4]. The present study focuses on investigating the thermodynamic behaviour and ionic conductivity of various salt-solvent lithium mixtures over a range of temperatures. Simulation measurements were conducted for LiPF₆, LiBF₄ and LiClO₄ salts dissolved in binary and ternary mixtures of EC, DMC and PC. Conductivity was measured using an electrochemical impedance analyzer and the data were fitted using Arrhenius and Vant Hoff equations to extract thermodynamic parameters [5].
Key Words: Ionic conductivity1, Thermodynamic 2 parameters , Lithium salts3, Solvent mixtures4, Electrolyte systems5.
1. INTRODUCTION:
The calculated negative Gibbs free energy values (ΔG) indicate that the ion transport process is spontaneous. The positive enthalpy (ΔH) values reflect endothermic ion dissociation, while the positive entropy (ΔS) values suggest an increase in molecular disorder and solvent reorganization during ion migration [6]. The results show that LiPF₆ in ECDMC mixtures exhibited the highest ionic conductivity due to better salt dissociation and solvent compatibility. The study demonstrates that optimizing solvent composition and temperature conditions can significantly improve the ionic conductivity and stability of electrolytes for lithium-ion batteries. Future work will aim to extend this thermodynamic and conductivity analysis to ionic liquidbased and polymer gel electrolytes to understand their temperature-dependent on the case transport mechanisms.
Lithium batteries (LIBs) have become the most dominant energy storage technology due to their high energy density, long cycle life and efficiency in portable electronics and electric vehicles. The electrolyte, composed of lithium salts dissolved in suitable solvents, plays a vital role in determining the ionic conductivity and overall electrochemical performance of the battery [1]. The transport of lithium relating electrodes is influenced by several thermodynamic factors such as Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), which govern the ionic dissociation, solvation behaviour and temperature dependence of conductivity [2]. Seeing the relationship between ionic conductivity and thermodynamic parameters provides deep insight into the physicochemical nature of ion-solvent interactions. Typically, lithium salts like LiPF₆, LiBF₄ and LiClO₄ are used with organic carbonate solvents such as ethylene carbonate
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Computational modeling using molecular dynamics (MD) and density functional theory (DFT) will be incorporated to reproduce ion-solvent collaborations and forecast thermodynamic parameters more accurately. Additionally,
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